CN1625868A - Methods of Roaming Between Wi-Fi and Cellular Networks - Google Patents

Abstract

The present invention relates to a method of roaming between a WLAN and a cellular network, which interconnects the WLAN and the cellular network based on a mobile IP system for smooth roaming. In data communications in a WLAN and/or a cellular network using a mobile IP system, a method of roaming between the WLAN and the cellular network, comprising the steps of: identifying a packet data serving node of a cellular network to which a specific mobile terminal IP address is assigned, notifying an access point management means of a WLAN located within a current service area of the mobile terminal of information on a current access state of the mobile terminal, the access point management means to which the mobile terminal has newly accessed requesting an address update to replace the address of the packet data serving node with its address, assigning an IP address to the mobile terminal according to the update result, and notifying the packet data serving node of it; and the packet data service node receiving the notification message from the access point management apparatus transmits data obtained during roaming caused by the movement to the access point management node, thereby implementing roaming from the cellular network to the WLAN. In a similar manner, roaming from the WLAN to the cellular network may be achieved.

Description

Methods of Roaming Between Wi-Fi and Cellular Networks

technical field

The present invention relates to a method of roaming between a wireless local area network (WLAN) and a cellular network, in particular to an improved method of roaming between a WLAN and a cellular network, which interconnects the WLAN and the cellular network based on a mobile IP system to smoothly roaming.

Background technique

Generally, WLAN services are distributed domestically and internationally based on the IEEE802.11b standard with a maximum data rate of 11 Mbps using a bandwidth frequency of 2.4 GHz. 802.1x is used for user authentication, and standards of 802.11i for security and 802.11e for quality of service are also being developed.

Here, the interconnection of WLAN and cellular network must be considered in order to provide flexible services by overcoming the coverage limitation of access points (APs). Therefore, incentives for the distribution of WLAN services worldwide and the interconnection of WLAN and cellular networks have attracted great attention.

The most reliable way to interconnect WLAN and cellular networks is to use Mobile IP. A common way to use Mobile IP is to disconnect the physical layer and reconnect it in one session. This operation takes several seconds according to existing protocols.

However, in order to provide real-time services such as image or voice communication, the disconnection and reconnection time must be reduced as much as possible. That is, when a terminal moves from one network to another, the re-authentication and re-access procedures of the terminal must be performed within a short time. Therefore, there is a great need for a roaming method that can reduce the time spent to support mobility between WLAN and cellular networks.

Contents of the invention

Correspondingly, the main purpose of the present invention is to provide a method for roaming between WLAN and cellular network, through which a dual-mode terminal capable of accessing WLAN and cellular network moves from a WLAN service area to a cellular service area or vice versa. Roaming is supported, thereby reducing the time required for roaming, and roaming suitable for real-time services can be supported.

Another object of the present invention is to provide a method for roaming between WLAN and cellular networks, which can prevent data loss during roaming as much as possible, because unlike voice services, data maintenance is faster than real-time performance in data services. more important.

That is, the present invention is devoted to implementing a roaming method between a WLAN and a cellular network to minimize data loss and reduce roaming time.

In order to achieve the above object of the present invention, in the data communication in the WLAN and/or the cellular network using the mobile IP system, a roaming method between the WLAN and the cellular network comprises: a first step, identifying a specific mobile terminal The packet data serving node of the cellular network of IP address distribution notifies the access point management device about the current access status of the mobile terminal to the access point management device of the WLAN within the current service area of the mobile terminal; in the second step, the newly accessed mobile terminal The access point management device requests to update the address to replace the address of the packet data service node with its address, according to the update result, distributes the IP address to the mobile terminal, and notifies it to the packet data service node; and the third step, from the access point The packet data service node that the point management device receives the notification message transmits data obtained during roaming caused by moving to the access point management node, thereby enabling roaming from the cellular network to the WLAN.

According to another aspect of the present invention, in data communication in a WLAN and/or a cellular network using a mobile IP system, a method for roaming between a WLAN and a cellular network includes: a first step of identifying a particular mobile The access point management device of the WLAN assigned by the terminal IP address notifies the information of the current access status of the mobile terminal to the packet data service node of the cellular network within the current service area of the mobile terminal; in the second step, the newly accessed mobile terminal The packet data service node requests to update the address to replace the address of the access point management device with its address, according to the update result, distributes the IP address to the mobile terminal, and notifies it to the access point management device; and the third step, from the packet The access point management device of the data service node receiving the notification message transmits data obtained during roaming caused by moving to the packet data service node, thereby realizing roaming from the WLAN to the cellular network.

Description of drawings

FIG. 1 is a flowchart describing the concept of the Mobile IP system of the present invention;

FIG. 2 is a flow chart describing the concept when operating alone with a WLAN interconnected with the cellular network operating over Mobile IP shown in FIG. 1;

Fig. 3 shows in the roaming method between WLAN and cellular network according to the preferred embodiment of the present invention, when carrying out roaming from the cellular network shown in Fig. 1 to the WLAN shown in Fig. 2 the diagram of the network interconnection method flow chart;

Fig. 4 shows in the roaming method between WLAN and cellular network according to the preferred embodiment of the present invention, when performing the roaming from WLAN shown in Fig. 2 to the cellular network shown in Fig. 1 the diagram of the network interconnection method flow chart;

Figure 5 shows the format of the Con-Inform message generated and sent in Figures 3 and 4; and

FIG. 6 shows the format of the Con-Notify message generated and transmitted in FIGS. 3 and 4 .

Detailed ways

A roaming method between a WLAN and a cellular network according to a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 is a flowchart describing the concept of the Mobile IP system of the present invention. Referring to FIG. 1, packet data serving nodes PDSN1 and PDSN2 (110: 111 and 112) are nodes located in a cellular network of a CDMA 2000 1x network for performing a packet data handover function. The home agent (HA) 120 is a location registration device located in the network and is used to register a location when the mobile terminal (MT) 11 requests location registration through the PDSN 110. Here, the HA 120 includes a plurality of IP address resources, links the plurality of IP address resources to the identification information of the PDSN 110 and the MT 11 based on the location registration request message, and dynamically allocates IP addresses and generates address registration request messages, address The update request message and the address deletion request message serve as an address update message for updating an assigned IP address. A domain name server (DNS) 130 is address management means for registering, updating, or deleting addresses assigned to the MT 11 based on an address update message from the HA 120 (i.e., an address registration request message, an address update request message, or an address deletion request message). .

The concept of the Mobile IP system will be described below with reference to FIG. 1 .

When a user MT 11 with a specific host name (han) requests location registration to HA 120 through PDSN1 111 (S201 and S202), HA 120 allocates one of the IP address resources (ip1) to the corresponding IP address resource based on the location registration request message from PDSN1 111. The MT 11 (S203) of the MT 11 registers the location (S204) by linking the assigned IP address resource ip1 of the host name han of the MT 11 and the identification information of the current access PDSN1 111 (S204), and requests han to the DNS 130 based on the location registration request message : Registration of the IP address of ip1 (S205). DNS 130 registers han:ip1 in response to this request (S206).

When accessing PDSN1 111 and registering the MT 11 of its position and IP address resources to move and request HA 120 to carry out position registration (S207 and S208) (S207 and S208) with host name han and the assigned IP address ip1 to HA 120 by PDSN2 112, HA 120 based on the information from The location registration request message of PDSN2 112 recognizes that the registered PDSN of han:ip1 has changed from PDSN1 111 to PDSN2 112, and registers a location by linking han:ip1 to the identification information of PDSN2 112 (S209).

The HA 120 allocates IP address resources according to the location registration request message, registers the assigned IP address, confirms receipt of the registered location registration request message of han:ip1, and calculates non-reception time (S210). When the non-receiving time exceeds a predetermined time (S211), the HA 120 requests the DNS 130 to delete the registered han:ip1 (S212). The DNS 130 deletes the han:ip1 registration information based on the deletion request message (S213), and notifies the HA 120 of deletion completion so as to dynamically allocate the allocated address resource ip1 to another terminal (S214).

FIG. 2 is a flowchart describing the concept when a WLAN interconnected with the cellular network operating on the Mobile IP basis shown in FIG. 1 operates alone. In FIG. 2 , reference numeral 12 denotes a mobile terminal having a WLAN communication function such as a notebook PC, reference numeral 20 denotes an access point to which the mobile terminal 12 wirelessly accesses for communication, and reference numeral 30 denotes an access point on the mobile terminal 12. An authentication/charging server for authentication and charging during data communication.

When the mobile terminal 12 accesses the access point 20 (S251), it is authenticated by the authentication/billing server 30 according to the 802.1x authentication procedure (S252). Here, 802.1x is one of existing methods including MD-5, TLS, SRP, and OTP.

After completing the verification process, the access point 20 sends a message access-request (start) to notify the verification/charging server 30 that charging starts so as to start charging (S253), and provides data services to the mobile terminal 12 until the access in S251 End (S254).

Fig. 3 shows in the roaming method between WLAN and cellular network according to the preferred embodiment of the present invention, when carrying out roaming from the cellular network shown in Fig. 1 to the WLAN shown in Fig. 2 the diagram of the network interconnection method flow chart.

Fig. 4 shows in the roaming method between WLAN and cellular network according to the preferred embodiment of the present invention, when performing the roaming from WLAN shown in Fig. 2 to the cellular network shown in Fig. 1 the diagram of the network interconnection method flow chart.

In the embodiment shown in Figures 3 and 4, the cellular network is a CDMA 2000 1x network, and the Base Station Controller (BSC) 410, Packet Data Serving Node (PDSN) 420 and Home Agent (HA) 430 shown in Figure 3 represent Nodes of the cellular network shown in FIG. 1 , an access point (AP) 510 and an access point management device (APM) 520 represent nodes of the WLAN shown in FIG. 2 . APM 520 is newly installed in WLAN as a node that manages AP 510 and supports mobility to have a function corresponding to PDSN 420, and authentication/accounting server (AAA) 440 is used to authenticate and verify users of the cellular network and WLAN Fee-based server. In addition, the mobile terminal (MT) 10 is a dual-mode terminal, which can access the cellular network shown in FIG. 1 and the WLAN shown in FIG. 2, and adopts a mobile IP stack. The PDSN 420 and the APM 520 are operated as nodes for performing a Mobile IP-based handover function in each network in order to support mobility of the MT 10.

The roaming method from the cellular network to the WLAN will be described below with reference to FIG. 3 .

The MT 10 located in the cellular network performs channel and R-P establishment through the BSC 410 including the base station and the PDSN 420. That is, the MT 10 accesses the BSC 410 to perform bidirectional channel setup (CH setup) (S301), and the channeled BSC 410 performs bidirectional R-P setup with the PDSN 420 (S302), which has been disclosed by the prior art.

Thereafter, the MT 10 and the PDSN 420 perform Point-to-Point Protocol (PPP) authentication (S303). Correspondingly, the PDSN 420 sends access requests to the HA 420 and the AAA 440 respectively and receives responses so that the HA 430 and the AAA 440 can perform related functions (S304). This process is also known from the prior art.

The Mobile IP stack of the MT 10 performs a predetermined procedure with the PDSN 420 to receive an IP address (MIP request and advertisement) (S305).

After executing the protocol related to Mobile IP of S305, MT 10 requests location registration (Registration Request) to HA 430 through PDSN 420 using Network Access Identifier (NAI), ID and password (S306 and S307). The HA 430 sends an Access Request message Access Request to the AAA 440 to start charging (S308), and receives a response message Access Response (S309). As a result, when user authentication and mobile IP registration by AAA 440 and HA 430 succeed, HA 430 assigns an IP address to MT 10 through PDSN 420 and BSC 410 as a response to S306 and S307 (S310 and S311). Except for the processing related to AAA 440, the process of S306 to S311, that is, the process of location registration and IP address allocation is the same as the process of S201 to S206, and thus the detailed description thereof is omitted.

By S311, the PDSN 420 currently accessed by the MT 10 detects the current location (that is, the base station area) and the registration response of the MT 10, and sends a message to the management device as the AP 510 in the area through the Con-Inform message shown in Figure 5 The APM 520 notifies the current access state of the MT 10 (S312).

With reference to Fig. 5, the Con-Inform message includes protocol version and its length (for example, 1 byte), message identifier and its length (for example, 2 bytes), packet length and its length (for example, 2 bytes), sending Party IP address and its length, client MAC address and its length, user ID and its length, user NAI and its length, user password and its length, serial number from 0 to 2048 and its length (for example, 2 bytes) ,and others.

When the MT 10 moves to the WLAN area to access, it is authenticated by the AP 510 and the APM 520 according to 802.1x (S313 and S314). Here, when the APM 520 receives the information of the MT 10 at S312, it requests to update the binding table (roaming registration) of the HA 430 using its address as a care-of address (COA) (S315).

Thereafter, when requested by the MT 10, the APM 520 sends the assigned IP address updated in S315 to manage the MT 10 (DHCP request and response) (S316). This address is required to send data from APM520 to MT 10.

APM 520 utilizes the Con-Notify message shown in Figure 6 to notify PDSN 420 of sending data in S312 that roaming has been performed (S317).

As shown in Figure 6, the Con-Notify message includes the protocol version and its length (for example, 1 byte), the message identifier and its length (for example, 2 bytes), the packet length and its length (for example, 2 bytes) , sender IP address and its length, connection context and its length, sequence number from 0 to 2048 and its length (eg, 2 bytes), and others.

Finally, the PDSN 420 receiving the Con-Notify message in S317 sends the data obtained during the roaming process to the APM 520 (interval data forwarding) (S318).

A roaming method from a WLAN to a cellular network will be described below with reference to FIG. 4 .

The MT 10 located in the WLAN accesses the AP 510 (S601), and is authenticated by AAA according to the 801.1 authentication process (S602).

The Mobile IP stack of the MT 10 performs a predetermined process with the APM 520 to receive an IP address (MIP request and notification) (S603).

After executing the protocol related to Mobile IP in S603, MT 10 utilizes NAI value, ID and password to request location registration (registration request) to HA 430 through APM 520 (S604 and S605). The HA 430 sends an Access Request message Access Request to the AAA 440 to start charging (S606), and receives a response message Access Response (S607). As a result, when user authentication and mobile IP registration by AAA 440 and HA 430 succeed, HA 430 assigns an IP address to MT 10 through APM 520 and AP 510 as a response to S604 and S605 (S608 and S609).

The process from S604 to S609, that is, the process of location registration and IP address allocation is the same as the process from S306 to S311. That is, the AP 510 and the APM 520 as constituent nodes of the WLAN have similar/same functions as the base station/BSC 410 and the PDSN 420 as constituent nodes of the cellular network.

Through S609, the APM 520 currently accessed by the MT 10 detects the current location (that is, the AP area) and the registration response of the MT 10, and sends a message to the base station/BSC 410 used in the area through the Con-Inform message shown in Figure 5 The PDSN 420 notifies the current access state of the MT 10 (S610).

When the MT 10 moves to the cellular network area, the MT 10 located in the cellular network performs channel establishment and R-P establishment (S611 and S612) as shown in S301 to S303 of FIG. 3 through the BSC 410 and the PDSN 420. Thereafter, the MT 10 and the PDSN 420 perform PPP authentication (S613).

Here, when the PDSN 420 receives information on the MT 10 in S610, it requests to update the binding table (roaming registration) of the HA 430 using its address as the COA (S614). It corresponds to S315 in FIG. 3 .

When requested by the MT 10, the PDSN 420 transmits the allocated IP address updated in S614 to manage the MT 10 (DHCP request and response) (S615). This address is required to send data from PDSN 420 to MT 10.

The PDSN 420 notifies the APM 520 sending data in S610 that the roaming has been performed (S616) using the Con-Notify message shown in FIG. 6 . Finally, the APM 520 receiving the Con-Notify message in S616 sends the data obtained during roaming to the PDSN 420 (interval data forwarding) (S617). The process from S615 to S617 corresponds to the process from S316 to S318 shown in FIG. 3 .

The invention is not limited to the aforementioned embodiments. For example, the present invention can be applied to 802.11a in which WLAN uses a frequency of 5 GHz bandwidth. That is, the present invention can be implemented in various forms without departing from the spirit of the essential characteristics of the present invention.

Industrial applicability

To sum up, the roaming method between WLAN and cellular network can support roaming that is more suitable for real-time services by reducing roaming time, and can prevent data loss during roaming. That is, the present invention can minimize data loss and reduce the time required for roaming.

Claims (6)

1. in the WLAN and/or the data communication in the cellular network that use mobile IP system, a kind of method of roaming between WLAN and cellular network comprises:

First step, identification to the packet data serving node of the cellular network of the IP address assignment of a specific portable terminal to the access point management devices notice of the WLAN that is positioned at this portable terminal current service zone information about the current access state of this portable terminal;

The access point management devices request scheduler that second step, portable terminal insert recently to replace with its address the address of packet data serving node, according to upgrading the result to this portable terminal distributing IP address, and it is notified to packet data serving node; And

Third step is sent in the data that obtain the roam procedure that the access point management node caused by moving to from the packet data serving node of access point management devices receiving notice message, realizes the roaming from the cellular network to WLAN thus.

2. in the WLAN and/or the data communication in the cellular network that use mobile IP system, a kind of method of roaming between WLAN and cellular network comprises:

First step, identification to the access point management devices of the WLAN of the IP address assignment of a specific portable terminal to the packet data serving node notice of the cellular network that is positioned at this portable terminal current service zone information about the current access state of this portable terminal;

The packet data service node requests scheduler that second step, portable terminal insert recently to replace with its address the address of access point management devices, according to upgrading the result to this portable terminal distributing IP address, and it is notified to the access point management devices; And

Third step is sent in the data that obtain the roam procedure that packet data serving node causes by moving to from the access point management devices of packet data serving node receiving notice message, realizes the roaming from WLAN to the cellular network thus.

3. according to the method for claim 1 or 2, wherein the notification message in the first step comprises protocol version and length, message identifier and length thereof, block length and length thereof, transmit leg IP address and length, client mac address and length thereof, user ID and length thereof, user NAI and length, user cipher and length thereof, sequence number and length thereof.

4. according to the method for claim 1 or 2, wherein the notification message in second step comprises protocol version and length, message identifier and length thereof, block length and length thereof, transmit leg IP address and length thereof, connection context and length, sequence number and length thereof.

5. according to the method for claim 1 or 2, wherein packet data serving node and access point management devices are carried out handoff functionality based on mobile IP to support the mobility of portable terminal.

6. according to the method for claim 1 or 2, wherein portable terminal is a dual-mode terminal, and it can insert cellular network and WLAN and adopt mobile IP storehouse.

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